1. Field of the Invention
This invention is directed to an improved petroleum residua upgrading process comprising hydrotreating of resids in the presence of a metal-containing amorphous lanthana-alumina-aluminum phosphate catalyst.
2. Discussion of the Prior Art
Many petroleum based stocks contain contaminants such as, for example, sulfur, nitrogen and metals. It is desirable, particularly if these stocks are to be further processed, that the contaminants be removed. This is an operation usually requiring use of a catalyst.
It has been conventional in the art to effect contaminant removal, such as sulfur removal from hydrocarbon stocks, by subjecting them to treatment with hydrogen at elevated temperature and pressure while in contact with a catalyst containing hydrogenating components. Typically the hydrogenating components of such known catalysts are Group VIB or VIII metals, or other oxides or sulfides. These hydrogenating components may be supported on a variety of well known carriers, such as, for example, crystalline and amorphous materials. Crystalline materials include zeolites and other silicates. Amorphous materials include silica, silica-alumina, clays, oxides of zirconium, titanium, cerium, thorium, lanthanum, calcium and magnesium, and phosphates of zinc, zirconium, thorium, cerium, calcium, magnesium and aluminum. A listing of such materials appears in Australian Pat. No. 31365/84.
Zeolites, both natural and synthetic, have been demonstrated to be effective catalyst supports. A large variety of synthetic zeolites are known, as illustrated by zeolite A (U.S. Pat. No. 2,882,243), zeolite X (U.S. Pat. No. 2,882,244), zeolite Y (U.S. Pat. No. 3,130,007), zeolite ZK-5 (U.S. Pat. No. 3,247,195), zeolite ZK-4 (U.S. Pat. No. 3,314,752), zeolite ZSM-5 (U.S. Pat. No. 3,702,886), zeolite ZSM-11 (U.S. Pat. No. 3,709,979), zeolite ZSM-12 (U.S. Pat. No. 3,832,449), zeolite ZSM-20 (U.S. Pat. No. 3,972,983), ZSM-35 (U.S. Pat. No. 4,016,245) and zeolite ZSM-23 (U.S. Pat. No. 4,076,842), merely to name a few.
Aluminum phosphates are taught in U.S. Pat. Nos. 4,310,440; 4,385,994; 4,365,095; 4,361,705; 4,222,896; 4,210,560; 4,179,358; 4,158,621; 4,071,471; 4,014,945; 3,904,550 and 3,697,550, for example. Microporous aluminum phosphates have a composition typified as: ps EQU xR:Al.sub.2 O.sub.3 :(1.0.+-.0.2)P.sub.2 O.sub.5 :yH.sub.2 O
wherein R is an organic amine or quaternary ammonium salt entrapped within the aluminum phosphate and plays a role as crystallization template, x and y representing the amounts of R and H.sub.2 O needed to fill the microporous voids.
U.S. Pat. No. 4,440,871 teaches material called silicoaluminophosphate without non-aluminum metals. Individual silicoaluminophosphate structures are shown in U.S. Pat. Nos. 4,623,527; 4,632,811 and 4,639,357. An antimonophosphoaluminate structure is taught in U.S. Pat. No. 4,619,818.
The phosphorus-substituted zeolites of Canadian Pat. Nos. 911,416; 911,417 and 911,418 are referred to as "aluminosilicophosphate" zeolites. These latter materials containing silicon, aluminum and phosphorus are characterized by the general formula: EQU M.sub.(x-y) :x(AlO.sub.2.sup.-):(SiO.sub.2):y(PO.sub.2.sup.+):zH.sub.2 O
wherein M is a monovalent cation, x is approximately 0.125-1.5, y is 0.05-1.0 and z is the number of hydration water molecules. Structural replacement of silicon with phosphorus has been realized in materials called silica clathrates (West German Pat. No. 3,128,988).
U.S. Pat. No. 4,363,748 describes a combination of silica and aluminum-calcium-cerium phosphate as a low acid activity catalyst for oxidative dehydrogenation. Great Britain Pat. No. 2,068,253 discloses a combination of silica and aluminum-calcium-tungsten phosphate as a low acid activity catalyst for oxidative dehydrogenation. U.S. Pat. No. 3,801,704 teaches an aluminum phosphate treated in a certain way to impart acidity. U.S. Pat. No. 4,228,036 teaches an alumina-aluminum phosphate-silica matrix as an amorphous body to be mixed with zeolite for use as cracking catalyst. U.S. Pat. No. 3,213,035 teaches improving hardness of aluminosilicate catalysts by treatment with phosphoric acid.
U.S. Pat. No. 4,382,877 describes a catalyst composition of a particular metal on a support containing (1) a compound of magnesium, calcium, strontium or barium, (2) alumina and (3) aluminum phosphate, the support having an average pore radius area of from 10 to 300 Angstroms, a surface area of from 100 to 350 m.sup.2 /g and a pore volume of from 0.3 to 1.5 cc/g. Various combinations of metal compounds, such as calcium, strontium, barium and magnesium oxide, with alumina and aluminum phosphate are described as catalyst supports in U.S. Pat. No. 4,382,878.
U.S. Pat. No. 4,376,067 describes a catalyst support containing various combinations of metal compounds, including zinc, cadmium, magnesium, calcium, strontium and barium compounds, alumina and aluminum phosphate. Magnesia-alumina-aluminum phosphate support material and its synthesis is described in U.S. Pat. No. 4,210,560. Use of a magnesia-alumina-aluminum phosphate supported catalyst for cracking is described in U.S. Pat. No. 4,179,358. U.S. Pat. No. 3,755,146 describes a high surface area catalyst support material comprising alumina, silica, titania, zirconia, boria and combinations thereof.
U.S. Pat. No. 2,876,266 describes an active silicophosphoric acid or salt phase of an amorphous material prepared by absorption of phosphoric acid by premolded silicates, e.g. aluminosilicates.
The importance of pore size distribution in catalysts or catalyst carriers is taught in U.S. Pat. No. 4,328,127.
Hydrotreating of residua may be defined simply as removal of sulfur, nitrogen and metal compounds by selective hydrogenation. The hydrotreating catalysts used commercially are cobalt plus molybdenum or nickel plus molybdenum used in the sulfided forms and impregnated on an alumina base. The hydrotreating operating conditions are about 1000 to 2000 psi hydrogen and about 700.degree. F. However, the desulfurization reactions are invariably accompanied by small amounts of hydrogenation and hydrocracking, the extent of which depends on the nature of the feedstock and the severity of desulfurization. U.S. Pat. Nos. 3,891,541 and 4,351,717 teach residua hydrotreating. The catalysts taught in the latter two patents, the disclosures of which are incorporated herein by reference, comprise commercial hydrogenating components on alumina supports having particular pore size distributions.
This invention relates to a petroleum residua upgrading process. It comprises hydrotreating atmospheric or vacuum resids in the presence of a catalyst. The catalyst is a metal-containing amorphous lanthana-alumina-aluminum phosphate ("LAAP"). Neither the prior art mentioned above nor any art known to applicants relates to the use of an LAAP-supported catalyst for demetallization and desulfurization of resids. It is only applicants who have discovered hydrodemetallization advantages obtained through use of such catalysts. Moreover, the pore size distribution of applicant's material is distinctive for such materials. All this is neither disclosed nor suggested in the art.